Statement of the Technical Field
The inventive arrangements relate to Vacuum Packaging Appliances (“VPA”). More particularly, the invention concerns VPA employing solid state proximity detectors for detecting when a container is inserted into the VPA.
Description of the Related Art
Various appliances are used for vacuum packaging purposes to protect perishables and other products against oxidation. Such appliances typically use heat sealing elements to form seals at open ends of containers. The heat sealing elements can include one heat sealing bar or two adjacent heat sealing bars over which an open end of a container is placed. Prior to formation of a heat seal, a container may be evacuated of excess moisture and air through the use of at least one vacuum pump. The evacuation of moisture and air from the container minimizes the spoiling effects of oxygen on perishables and other products.
Such appliances may also comprise a means for detecting when the container is properly inserted therein. The means typically comprise mechanical flags configured to initiate the recognition that a container has been inserted into the respective appliance. For example, at least one mechanical structure (e.g., pendulums and springs) is provided within the appliance to detect whether a container material is inserted properly within the appliance (e.g., across a majority of an entire length of a vacuum chamber trough). Such detection occurs when at least a portion of the mechanical structure is caused to move. Movement of a mechanical flag is accomplished by inserting more bag material into the appliance.
Despite the advantages of the mechanical flag approach to detect when container material is inserted properly into a vacuum appliance, it suffers from certain drawbacks. For example, the mechanical structure could cause container material to wrinkle, thereby resulting in a false detection or other error. Also, the mechanical structures of this approach are relatively mechanically complex and expensive.